TOKYO — Sam Stosur knocked two-time champion Maria Sharapova out of the Pan Pacific Open on Thursday, reaching the semifinals with a 6-4, 7-6 (10) victory over the Russian.
Stosur broke Sharapova to go up 5-3 in the second set but then lost nine straight points as the Russian sent the match to a tiebreaker, which Stosur won on her fifth match point when Sharapova returned long.
"I knew that I had lost nine points and was just trying to stop the momentum swing," Stosur said. "I wasn't thinking about the points I lost but was focusing on how I was going to make the next points."
Top-ranked Victoria Azarenka withdrew after a bout of dizziness in her third-round match on Wednesday, sending Angelique Kerber of Germany to the semifinals.
"Before the tournament on Sunday I was starting to feel not really good," Azarenka said. "I haven't really been doing better since then. Just low energy, you could tell by the matches I wasn't my usual self. But it took too much energy over the last two matches to really push and today it's just not really possible for me."
Also, Nadia Petrova of Russia, trailing 4-1 in the second set, overcame sixth-seeded Sara Errani of Italy 3-6, 7-5, 6-3. She will next face Stosur today. Defending champion and third-seeded Agnieszka Radwanska of Poland beat former No. 1 Caroline Wozniacki 6-4, 6-3 in the late quarterfinal and will face Kerber in the semifinals today.
For Sharapova, it was only her second loss in 11 matches against Stosur, who has reached her first semifinal match since the French Open.
Sharapova, who won the tournament in Tokyo in 2005 and 2009, struggled with her serve and had five double-faults. "She played a very steady game and I had a few more unforced errors than I would have liked," Sharapova said. "It's disappointing to lose but you have to take every disappointment and turn it into a positive. It's really about thinking what I can do to improve for the next tournament."
At Kuala Lumpur, Malaysia, Juan Monaco of Argentina reached the quarterfinals in his Malaysian Open debut but fellow seeds Alexandr Dolgopolov of Ukraine and Feliciano Lopez of Spain lost.
Second-seeded Monaco defeated Taiwanese wild card Jimmy Wang 6-4, 7-5. The Argentine responded to losing his serve three times by breaking Wang five times.
Fourth-seeded Dolgopolov lost to Alejandro Falla of Colombia 6-3, 3-6, 6-3.
"I started really bad and missed a lot of balls," Dolgopolov said. "I came back in the second set, but it was an up and down match."
Falla will face Julien Benneteau of France.
Dutchman Igor Sijsling upset No. 5 Lopez, 7-6 (0), 7-6 (2). They played impeccably on serve with 11 aces each and no break points conceded, but Lopez struggles in both tiebreaks. Kei Nishikori of Japan rallied past Albert Ramos of Spain 6-7 (5), 6-2, 6-1. Today, the third-seeded Nishikori will play Nikolay Davydenko, whom he beat in the London Games.
At Bangkok, Gael Monfils edged sixth-seeded Victor Troicki of Serbia 7-5, 7-5 in the second round of the Thailand Open.
Monfils also reached the quarterfinals last week in Metz, his first tournament since May after being sidelined by a right knee injury.
The Frenchman used five breaks of serve to trump the three he lost, beating Troicki a third straight time. Monfils will meet 2009 champion Gilles Simon, who defeated Go Soeda of Japan 6-4, 6-4.
Fernando Verdasco of Spain edged Donald Young of the U.S. 7-5, 6-4, and Bernard Tomic of Australia reached his first quarterfinal since April, rallying past Dudi Sela of Israel 4-6, 6-3, 6-4.
Also, third-seeded Milos Raonic of Canada beat Ivo Karlovic of Croatia 7-6 (3), 6-4 in the first matchup of big servers. Raonic had 14 aces to nine for Karlovic, and converted his only break point chance. "I was a bit hesitant in the first set, and tried to figured out (the indoor court) in the second," said Raonic, who will face Jarkko Nieminen of Finland.